The rules also say u have to pay $1 a game on every game.
At the end of the day, I guess u have to charge something because if there is prize money involved, and u have to move around/supply machines/fuel/running costs of supplying a place to hold a competition etc, it ALL adds up $. Its a fine balance of charging too much or too little.
* It would help if they had a list of machines that will be available and some photos of people lined up to play etc would be better for the site.